package com.atguigu.gulimall.product.service.impl;

import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        //1.查询所有分类
        //baseMapper 相当于CategoryDao    因为继承了ServiceImpl中的泛型为CategoryDao，在ServiceImpl中有个baseMapper变量就是CategoryDao
        List<CategoryEntity> entities = baseMapper.selectList(null);

        //2.组装成父子的树形结构
        //2.1找到所有的一级分类     stream流filter中因为只有一个参数所以小括号可以省略，因为只有一条语句所以大括号也可以省略
        List<CategoryEntity> level1Menus = entities.stream().filter((categoryEntity) -> {
            return categoryEntity.getParentCid() == 0;
        }).map((menu)->{
            menu.setChildren(getChildrens(menu,entities));
            return menu;
        }).sorted((menu1,menu2)->{
            return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());
        }).collect(Collectors.toList());


        return entities;
    }

    @Override
    public void removeMenusByIds(List<Long> asList) {
        baseMapper.deleteBatchIds(asList);
    }

    /**
     * 递归查找子分类
     * @param root
     * @param all
     * @return
     */
    public List<CategoryEntity> getChildrens(CategoryEntity root,List<CategoryEntity> all){

        List<CategoryEntity> children = all.stream().filter((categoryEntity) -> {
            return categoryEntity.getParentCid() == root.getCatId();        //找出除一级分类的其它分类（二级分类及以下）
        }).map((categoryEntity) -> {
            categoryEntity.setChildren(getChildrens(categoryEntity, all));  //接着递归找出下一级分类（三级分类及以下）
            return categoryEntity;
        }).sorted((menu1, menu2) -> {
            return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());
        }).collect(Collectors.toList());

        return children;
    }

}